The model study of the Spillway and Tunnel for Dorena Dam was conducted at the Bonneville Hydraulic Laboratory, Bonneville, Oregon. The general purpose of this study was to determine by means of a 1-to-50 scale model the hydraulic characteristics of the originally-designed spillway, stilling basin, and outlet works of Dorena Dam and to develop satisfactory alternate designs for any of the features found to be hydraulically inadequate.

Model investigations of the gravity spillway plan for Dorena Dam, Row River, Oregon, were conducted at the Bonneville Hydraulic Laboratory for the Portland District, Corps of Engineers, after decision was made by the Office, Chief of Engineers to abandon the chute-type spillway and cylinder-gate-controlled outlet works design. The general purpose of the investigations reported was to check the adequacy of the original gravity-type-spillway design and, where possible, to make revisions in design which would improve hydraulic efficiency.